Motor grader blade adjusting mechanism



May 20, R. D PAIGE ET AL MOTOR GRADER BLADE ADJUSTING MECHANISM Filed Sept. 19. 1966 Sheet of s INVENTORS POSS/ELL 2. PAGE BY 'E/VE B. E/lSTERL/NG May 20, 1969 PAGE ETAL 3,444,936

MOTOR GRADER BLADE ADJUSTING MECHANISM Filed Sept. 19. 1966 Sheet 2 of 3 INVENTORS PUSSELL .D PAGE BYGE/VE B. EASTERL/NG ATTOFPNEVS -M41, an; 1 7% "May 20,1969 R. D. PAGE ETAL 3,444,936

MOTOR GRADER BLADE ADJUSTING MECHANISM Filed Sept. 19. 1966 Sheet 3 of s INVENTORS PUSSELL D. PAGE BY GENE B. EASTERL/NG A TTOR/VEYS 3,444,936 MOTOR GRADER BLADE ADJUSTING MECHANISM Russell D. Page and Gene B. Easterling, Decatur, 11]., as-

signors to Caterpillar Tractor Co., Peoria, 111., a corporation of California Filed Sept. 19, 1966, Ser. No. 580,472 Int. Cl. E02f 3/12 U.S. Cl. 172-795 8 Claims ABSTRACT OF THE DISCLOSURE The blade of a motor grader is coupled to the blade circle thereof through a parallelogram linkage and control means are provided whereby the blade elevation may be changed without disturbing the tip setting. Conversely, the tip may be adjusted without changing the elevation. Both adjustments are effected rapidly from the drivers station and without operation of the primary blade position controls.

This invention relates to earthworking equipment and more particularly to a more readily controlled, rapid acting and more precise mechanism for adjusting the earthworking blade of a motor grader.

Motor graders generally require a complex of mechanisms for manipulating the blade into different positions. Typically means are provided for varying the depth of cut or vertical position of the blade, for changing the angle of the blade relative to the direction of travel of the grader, for adjusting the slope or inclination of the blade edge relative to the ground surface, for side-shifting or pivoting the blade transversely on the frame of the grader, and for adjusting the tip or degree of tilting of the blade. The means heretofore employed for effecting these blade movements have been somewhat interdependent with the result that certain specific changes could not be made without requiring compensating changes in certain others of the adjustments.

Several undesirable consequences result from this interdependence. Blade adjustments, for example, require complicated and taxing control lever manipulations on the part of the operator and cannot be made as rapidly as would be ideal from the standpoint of obtaining optimum motor grader performance.

In particular, the blade of a motor grader is carried on a drawbar which attaches to a forward portion of the grader by a ball and socket joint. The blade itself is fastened to an annular blade circle member mounted on a rearward portion of the drawbar in a rotatable manner. One of the principal conventional controls selectively rotates the blade circle relative to the drawbar and thus provides for adjusting the angling of the blade relative to the direction of movement of the grader. A pair of separately controlled lifts are also provided, one connecting to each side of the blade circle. By uniformly actuating both lifts, the blade may be raised or lowered and by differentially operating the lifts, blade slope is adjusted. Tip adjustments are generally made by still another mechanism situated between the blade and blade circle while side shifting is effected by further mechanism which pivots the entire drawbar and attached elements to one side.

An analysis of this standard structure will make it evident that operations of the two independent lifts to raise or lower the blade will very probably alter the slope thereof, an effect which is usually undesirable and which calls for further restorative control manipulations by the operator. Conversely, actuation of the two lifts to bring about a desired readjustment of the slope may very easily leave the blade at something other than the desired eleva- United States Patent "ice 3,444,936 Patented May 20, 1969 tion setting. Further, changing either the blade elevation or slope must affect the tip or tilt setting.

As a practical matter, any but the most skilled operator must usually follow up a particular operation of one of the controls with perhaps repeated adjustments of others thereof. This is not only undesirable in itself but may have important effects on the method of using the motor grader and the results obtained. Stepped cutting, in which relatively shallow layers of soil are removed by multiple passes, is made difficult due to the need for repeated complicated blade adjustments. Inasmuch as changing the depth of out has required independent adjustment of both ends of the blade, there is a risk of cutting undulations into the ground surface which are very difficult to remove by subsequent passes. In bank cutting, with the blade steeply sloped at the side of the grader, the operator commonly resorts to controlling the depth of cut by steering the vehicle rather than by using the direct blade position controls.

Thus the utility of motor graders can be greatly enhanced and the operation simplified if blade adjustments can be made more rapidly, preferably by a single control manipulation, and without disturbing other blade settings.

The present invention provides adjustable mechanism coupling the blade to the blade circle and providing for lifting or lowering of the blade relative to the circle through a single control manipulation and without affecting either the slope or tip of the blade. The mechanism further provides for rapid independent adjustment of tip from the operators station and is compatible with, and supplementary to, the standard blade adjustment mechanisms and controls, no basic modifications in the overall construction of the motor grader being required.

In addition to providing for much improved operator control over blade settings during routine operations, certain further advantages inhere in the invention. As the throat clearance or spacing between the blade and suprajacent blade circle structure can be easily changed from the operators station without disturbing slope setting, additional ground clearance can be obtained when needed for such purposes as overriding obstacles, moving out of ditches, or facilitating side shifting of the blade. The structure further allows periodic angular repositioning of the blade circle relative to the blade so that wear on the circle gear teeth from the drive pinion is not concentrated at a small segment of the circle.

Accordingly, it is an object of this invention to provide for more precise and complete control of the position of the blade of a motor grader.

It is an object of this invention to simplify and facilit-ate operation of a motor grader.

It is another object of this invention to provide mechanism for raising and lowering the blade of a motor grader without changing the slope or tip thereof.

It is still another object of the invention to provide for rapid control over the depth of cut of a motor grader blade by means of a single control means.

It is a further object of the invention to provide for lifting or lowering of the blade of a motor grader while maintaining the blade circle thereof in a fixed position.

It is still a further object of this invention to provide mechanism for coupling the blade to the blade circle of a motor grader with which the blade may be lifted or lowered without changing the slope or tip setting and with which the tip may be independently controlled from the operators station.

It is an additional object of the invention to provide mechanism for increasing the ground clearance of the blade of a motor grader without disrupting other settings thereof.

The invention, together with further objects and advantages thereof, will best be understood by reference to the 3 following specification taken together with the accompanying drawings, of which:

FIGURE 1 is a side elevation view of a motor grader embodying the invention;

FIGURE 2 is a perspective view of the forward portion of the motor grader of FIGURE 1 showing the blade thereof in an angled position and portions of the blade mounting structure broken out;

FIGURE 3 is a rear elevation view taken along line III-III of FIGURE 1 showing one end of the blade mounting and manipulating structure of the motor grader; and

FIGURES 4 to -6 illustrate different positions of the blade of the motor grader as effected by operation of the blade supporting linkage.

Referring now to the drawing and more particularly to FIGURE 1 thereof, the motor grader 11 will typically have an engine 12 and operators station 13 riding on rear wheels 14 and an arched main frame member 16 extending forwardly to a bolster 17 with front wheels 18 thereat. The earthworking blade or moldboard 19, of arcuate cross section, is drawn by a drawbar structure 21 having a front end fastened to bolster 17 by means such as a ball and socket joint 22 which provides for pivoting and swiveling of the drawbar and attached elements relative to the body of the motor grader 11.

Referring now to FIGURE 2, the drawbar structure 21 in this instance is formed by a pair of beams 23 which diverge rearwardly and are spanned at the rearmost end by a cross member 24. A rotatable blade circle member 26 is disposed against the underside of the rear portion of drawbar 21 and held hereon by shoes 27, shown in FIGURE 3, which are secured to the drawbar members and extend under the blade circle. Referring again to FIG- URE 2, the blade circle 26 is provided with gear teeth 28 so that the circle may be selectively rotated from the operators station through a gearbox 2'9 and drive linkage 31.

The blade 19 is attached to the blade circle 26 by a support and control assembly 32, to be hereinafter described in detail. which is advantageously fastened to the blade circle by disengageable means such as bolt 33. It has heretofore been the practice to weld or otherwise permanently secure the blade supporting structure -to the blade circle of a motor grader. As the angling of the blade 19 with respect to the direction of movement of the grader '11 tends to be kept within a limited range of settings for most operations, the result has been to concentrate wear of the blade circle teeth 28 at a limited segment of the blade circle. This in turn rapidly intro duces excessive free play into the mechanism and complicates maintenance problems. However, with the present construction, the blade circle 26 may be periodically unbolted from the blade support assembly 32 and rotated relative thereto after which the members are again bolted together. By this means, wearing of the teeth 28 may be uniformly distributed around the circle 26 greatly prolonging the life of the mechanism, providing greater rigidity, and simplifying maintenance.

The motor grader 11 using the present invention will generally be provided with a conventional set of blade adjustment controls supplementary to the more rapid and precise fine control provided by the invention. Referring again to FIGURE 1, typical standard controls include a pair of lifts 34, one extending along each side of the main frame member 16 and having linkage 36 connecting to the corresponding side of drawbar cross member 24 through a ball and socket joint 37. By operating both lifts 34, the drawbar 21, and thus the blade 19, may be raised or lowered. By differentially operating the lifts '34, the slope of the blade 19, with reference to a transverse horizontal axis through the motor grader, may be selectively changed. As has hereinbefore been pointed out, a change in either of these adjustments is likely to disturb the other necessitating further readjustments to restore the blade 19 to the preferred setting. Further, aside from the problems of control, the gear ratios customarily employed in the lifts 34 preclude very rapid changes in blade setting.

To pivot the drawbar 21, and thus the blade 19, sidewardly a standard side shifting mechanism 35 is mounted on frame 16 and connected through linkage 40 to cross member 24 of the drawbar at a ball and socket joint 38 thereon. Linkage 39 extends from the operator's station 13 to the hereinbefore described mechanism for rotating the blade circle 26 relative to the drawbar.

The present invention provides means supplementing the basic blade positioning controls described above for rapidly and precisely raising and lowering the blade 19 with respect to the blade circle 26 andvfor changing the degree of tip of the blade without affecting the other settings of the blade. Referring again to FIGURE 2, such means are contained within the blade control and support assembly 32.

Assembly 32 has a box member 41 which supports and partially encloses the other elements thereof and which provides a high strength connection between the blade circle 26 and blade 19. Member 41 has a rear wall 42 extending parallel to the blade 19 and a top wall 43 having a semicircular forward edge to receive the rear half of the blade circle 26 which is fastened to the top wall by bolts 33 as previously described. Referring now to FIGURE 3 in conjunction with FIGURE 2, box member 41 is further provided with a pair of spaced apart vertical side pieces 44 at each end which extend downwardly behind the blade 19 and which extend forwardly at the top along the blade circle 26. Preferably the side pieces 44, rear wall 42 and top Wal 43 are welded together to form a rigid high strength integral unit.

To join the blade 19 to the support and control assembly 32, an upper and lower rail, 46 and 47 respectively extend along the rear surface of the blade in paral el relationship thereto, the rails being secured to the blade and spaced therefrom by end brackets 48.

To provide for the desired movements, blade 19 is connected to the box member 41 through a parallelogram linkage which includes a pair of lower link members 49 each extending rearwardly from the lower rail 47 between one of the pairs of side pieces 44. The forward end of each link 49 is pivotable in a vertical direction about th lower rail 47 and the rearward end of each such link has a yoke 51 which, as best shown in FIGURE 3, is pivotably connected to the side pieces 44 by a transverse pin 52. Thus the lower link members 49 in conjunction with pivot pins 52 couple the blade 19 to member 41 and the blade circle 26 while allowing for vertical move ment of the blade as well as changes in the tip thereof.

To constrain such movements to the desired pattern, an additional link 53 is associated with each lower link 49 and has a lower end pivoted to pin 52 within the yoke 51 of the associated lower link. Each link 53 extends generally upward from the pivot pin 52 and has a yoke 54 at an intermediate position with one branch of the yoke being extended upward and slightly forward to an upper yoke 56. An angled third link member 57 is associated with each link 53 with the angle being pivoted by pin 55 to the intermediate yoke 54 thereof. One arm of each angled link member 57 extends generally forwardly and is pivotably engaged on the upper rail 46 of blade 19 while the other arm of the angled link member extends generally upward and is provided with a terminal yoke 58. One of a first pair of hydraulic jacks 59 is connected between the upper yoke 56 of each link -53 and a pivot pin 61 extending between side pieces 44 and situated forwa-rdly therefrom. One of a second pair of such jacks 62 is connected between each pivot pin 61 and the upper yoke 58 of the associated angled link member 57. To provide for transverse shifting of the blade 19 relative to the blade circle 26, an additional hydraulic jack 63 which is parallel to the blade may be connected between a blade end bracket 48 and a pair of brackets 64 which are slidable relative to the rails 46 and 47 and disposed one on each side of one set of links 49 and 57 as shown in FIGURE 3 in particular. The several jacks 59, 62 and 63 are of the double acting type and are preferably actuat d from the operators station 13 of the motor grader 11 by control means, providing for varying the rate of operation of the jacks, which are well understood within the art.

In operation, the basic positioning of the blade 19 may be accomplished by operating the standard controls, such as lifts 34, as hereinbefore described. Independently of these controls, the blade 19 may be rapidly raised or low ered with great precision by operating the jacks 62 and the tip or tilt of the blade may be adjusted by operating the additional set of jacks 59, these adjustments being made without significantly affecting each other and without changing the slope of the blade.

FIGURES 4, 5 and 6 illustrate the action of the above described linkage in response to operation of the jacks 59 and 62. As shown in FIGURE 4, both sets of jacks 59 and 62 may normally be set at intermediate degrees of extension and through the links 49, 53 and 57, the blade 19 held at a normal elevation and normal tip angle. Referring now to FIGURE 5, extension of the jacks 62 pivots angled link 57 about pin 55 thereby elevating the blade 19. Owing to the parallelogram linkage provided by the lower link 49, such elevation of the blade 19 will not affect the tip angle in the absence of movement of pivot pin 55 by operation of the jacks 59. As shown in FIGURE 5, however, jacks 59 have been contracted which pivots link 53 forward about pin 52 tipping the blade 19 to the full forward position. Referring now to FIGURE 6, extension of jacks 59 tips the blade 19 to the full back position while contraction of jacks 62 lowers the blade through action of the linkage in a reverse manner to that described above.

While FIGURES 5 and 6 illustrate extreme positions in both of the blade settings, the jacks 59 and 62 may be operated to effect any intermediate setting of the blade 19 with respect to either elevation or tip and either adjustment may be made without necessarily changing the other.

It will be apparent that elements of the mechanism may be varied from the form herein described without departing from the scope of the invention. Hydraulic jacks 59 and 62, for example, may be replaced with pneumatic cylinders or with equivalent mechanical controls. A single set of the linkages 49, 53 and 57 may be utilized if the members and associated pivot connections are made sufficiently strong or multiple sets of such linkage may be employed.

What is claimed is:

1. Blade supporting and positioning mechanism for amotor grader of the class having a blade circle for carrying the earthworking blade comprising, in combination, an adjustable parallelogram linkage coupling said blade to said blade circle and having vertically spaced upper and lower links coupling said blade to said blade circle, said upper and lower links each being connected to said blade by separate vertically spaced pivot means wherein said linkage is provided with a pivot for selectively tipping said blade about an axis parallel thereto, first control means coupled to said linkage for effecting changes in the spacing of said blade from said blade circle without substantially altering the tip inclination of said blade and second control means connected to said linkage for tipping said blade about said axis without substantially altering the elevation of said blade relative to said blade circle.

2. Blade supporting and positioning mechanism for a motor grader of the class having a blade circle for carrying the earthworking blade comprising, in combination, an adjustable parallelogram linkage coupling said blade to said blade circle and having vertically spaced upper and lower links coupling said blade to said blade circle, said upper and lower links each being connected to said blade by separate vertically spaced pivot means, wherein said linkage and blade are fastened to said blade circle by disengageable means whereby said blade circle may be angularly repositioned relative to said blade at periodic intervals, and first control means coupled to said linkage for effecting changes in the spacing of said blade from said blade circle Without substantially altering the tip inclination of said blade.

3. Blade supporting and positioning mechanism for a motor grader comprising in combination a blade support member attached to said blade circle and extending downwardly therefrom behind said blade, an adjustable linkage coupling said blade to said blade circle wherein said linkage comprises a first link having a first end pivotably connected to said blade and a second end pivoted to said support member, a second link connected to said support member for pivoting thereon about the same axis as said second end of said first link, a third link having a first end pivotably connected to said blade at a position thereon vertically spaced from that of said first end of said first link, said third link being pivoted to said second link, and first control means coupled to said linkage for affecting changes in the spacing of said blade from said blade circle, and said first control means being connected between said third link and said support member.

4. Blade supporting and positioning mechanism for a motor grader as defined in claim 3 and further comprising a second control means connected between said second link and said support member for selectively tipping said blade about said pivot axis of said second link.

5. Blade supporting and positioning mechanism for a motor grader as defined in claim 3 wherein at least a pair of each of said first, second and third links are provided between said blade and said support member, each set of said links being spaced apart along said blade.

6. Blade supporting and positioning mechanism for a motor grader as defined in claim 3 wherein said third link is angled with a first arm being pivoted to said blade and with the apex portion being pivoted to an intermediate portion of said second link, and wherein a second control means is connected between the second arm of said angled third link and said support member.

7. Blade supporting .and positioning mechanism for a motor grader as defined in claim 3 wherein said first control means comprises a double acting fluid operated jack connected between said third link and said support member above said blade, and further comprising a second double acting fluid operated jack connected between said second link and said support member above said blade.

8. Blade supporting and positioning mechanism for a motor grader as defined in claim 3 wherein said support member has a top wall and rear wall and side walls forming a housing partially enclosing said linkage and said control means.

References Cited UNITED STATES PATENTS 2,086,430 7/1937 Parkes 172795 X 2,565,337 8/1951 Allan. 2,604,708 7/ 1952 Washbond.

ABRAHAM G. STONE, Primary Examiner.

R. C. HARRINGTON, Assistant Examiner. 

